Gravity-feed bins for dispensing bulk-product inventory are used to dispense a wide variety of materials having a range of sizes and aggregate make-ups as diverse as hardware components, for example, nuts and bolts, to retail grocery food, such as pastas, cereals, nuts, coffee (either beans or ground), dried soup mixes, candies, spices, and the like. Generally, a gravity-feed bin is comprised of a hollow hopper-type reservoir enclosure having an inlet at an upper end utilized to fill the enclosure with bulk inventory, an outlet or chute at its lower end utilized to dispense the material, and a flow-control device located intermediate the upper and lower openings and controlled by a manually-actuated gate mechanism. This arrangement, in turn permits manipulation of the amount of inventory being dispensed during the interval the handle or other control device is actuated. In operation, as the inventory is being dispensed, the force of gravity causes the portion stored above in the reservoir to progressively migrate towards the lower end to replace the void left as portions of the inventory are dispensed. These types of bins generally include a downwardly angled or curving floor within the cavity that forms a slide to channel the stored inventory into a receptacle downstream from the outlet gate.
An alternate means for dispensing stored bulk inventory is to employ a bulk food dispenser generally known as a “scoop bin.” As the name suggests, a scoop bin typically comprises a hollow plastic bin, often having a hinged lid that is lifted to provide the consumer access to the stored contents. A hand scoop is then employed to gather the bulk product for placement into a container. While scoop bins are effective for dispensing a wider variety of product than a gravity type dispenser, they suffer from several major disadvantages, particularly in the area of hygiene, because of the contamination that can take place in these types of dispensers. Sources of contamination include germs that may be attached to the scoop or scoop handle being transferred to the stored product during dispensing or from external debris falling into the bin cavity when the bin's lid is lifted. Lastly, since the nature of scoop bins requires their openings to be located closer to the floor for access reasons, they are generally within the reach of children and others who are not hesitant to reach into the unsecured bins with potentially unclean hands in order to extract a sample, or even play with the bin contents. In addition, scoop bins also suffer from inventory shrinkage, both from pilferage and from accidental spillage.
As can be appreciated from the foregoing discussion, gravity-feed bins offer a multitude of advantages compared to other dispensing means, such as scoop bins, including convenience, ease of use and hygiene. However, current gravity-feed bins are not well-suited for dispensing oxidation-sensitive products such as tea. Oxidation is a chemical process that results in the browning of tea leaves and the production of flavor and aroma compounds in finished teas. Controlled oxidation usually begins after tea leaves are rolled or macerated, two processes that break down the cell walls in tea leaves. Chemically speaking, oxidation occurs when the polyphenols in the cell's vacuoles and the peroxidase in the cell's peroxisomes come in contact with the polyphenol oxidase in the cell's cytoplasm. The resulting reaction converts tea catechins into theaflavins and thearubigins. Theaflavins provide tea with its briskness and bright taste as well as its yellow color, and thearubigins provide tea with depth and body and its orange-brown color.
This conversion of catechins to theaflavins and thearubigins means that the longer the oxidation period, the lower the amount of catechins present in the finished tea. Also, during oxidation chlorophylls are converted to pheophytin, a pigment that lends to the dark color of oxidized teas. Lipids, amino acids and carotenoids also degrade during oxidation to produce some of tea's flavor and aroma volatile compounds. The oxidizing processing of tea leaves is a controlled process and employs moist, oxygen-rich air over time. Controlled oxidation may be halted by removing the oxygen from the finished tea product, which renders the enzymes responsible for the reaction inoperable. Further oxidation of the finished tea product, such as during storage in an oxygenated container or while housed in dispensing containers exposed to oxygenated ambient air such as in a point of sale environment is undesirable in that it can degrade the tea's quality and flavor. There is thus a need for a system utilizing an oxygen displacement substance, such as an inert gas, to conveniently and cost-effectively flush or purge oxygenated ambient air from dispensing containers holding oxidation-sensitive bulk product.